Old thread and my memory is a bit hazy, but I encountered no particular difficulty driving around the Ephesus area. It was actually pretty easy. Just keep in mind that petrol prices in Turkey are ridiculously high (about the highest in the world) and other forms of transportation (planes, buses) are very cheap. So a car is really only useful to explore a small geographic area, especially when there aren't other good touring options. I do remember that I had a cheap (and good) small group day tour in Cappadocia and, sure enough, it did snow that day in December. I was glad not to have to drive.